In Gradle we have The JVM Test Suite Plugin.
It enables me to create multiple test folders - for example except the standard src/test/groovy test directory, I also have src/integrationTest/groovy.
I'm also using The Test Report Aggregation Plugin.

The problem is that spock-reports do not create the report with integration tests when run on clean repo.
When there was previous run of the tests, there will be present in the report. But the point is to have it done also on clean repos.

Do you know how I could configure it, to run properly?

I should to add that integration test are run after unit tests.
I'm using 2.5.1-groovy-4.0 version.